1. Field
Example embodiments relate to non-volatile memory devices using graphene as a charge-trap layer by using a Schottky barrier between the graphene and a semiconductor substrate.
2. Description of the Related Art
Graphene has a 2-dimensional hexagonal carbon structure and research thereon is actively conducted as a material for replacing a semiconductor. In particular, graphene is a zero gap semiconductor, has metallic characteristics, and contacts metal to form a Schottky barrier therebetween.
As a non-volatile memory device, flash memory stores charges in a floating gate disposed between a control electrode and a channel. In order to prevent or inhibit leakage of charges at a floating gate, the floating gate is surrounded by an insulating layer.
In order to trap charges from a channel to a floating gate, the charges should pass through an insulating layer (tunneling oxide) therebetween, and thus a higher operation voltage is required.
As a charge-trap non-volatile memory device, a silicon-oxide-nitride-oxide-silicon (SONOS) memory device may have a lower operation voltage. A SONOS memory device has a structure in which a tunneling layer formed of silicon oxide, a charge-trap layer formed of silicon nitride, a blocking layer formed of silicon oxide, and a gate electrode are sequentially stacked on a semiconductor channel.